1. Field of the Invention
The present invention relates to an image forming apparatus, and more specifically, an image forming machine provided with a sheet storing unit which is useful for a duplex/composite copying operation.
2. Description of Related Art
In response to an increasing demand for the automation of a copying process, a sheet storing apparatus such as a sheet refeeder which is used for a duplex/composite copying operation and a finisher having a stapling function or a clipping function has been developed into various types which are of practical use.
However, in such a sheet storing apparatus, a sheet jam is inevitable, and the occurrence of a sheet jam is ordinarily detected by a combination sheet sensor and Limer unit. When the occurrence of a sheet jam is detected, a sheet jam reacting operation is executed by putting the copying system out of operation, and the jammed sheet is removed. Thereafter, when reset means such as a switch for detecting a front door open and closed, a switch for detecting a sheet storing apparatus ready, or the like is actuated, a sheet jam reaction resetting operation is executed by resetting every counter and every flag in a microcomputer and canceling the discontinuance of the copying system.
Conventionally, such a sheet storing apparatus does not have an exclusive jam reaction reset switch, and the sheet jam reaction resetting operation is executed in response to an on signal generated from a switch for detecting an outside frame of the sheet storing apparatus open and closed. An operator has to open the outside frame in order to remove a jammed sheet, so that when the operator closes the frame, and thereby the open/closed detection switch is turned on, it may be judged that the jammed sheet has been removed.
However, in reference to a sheet storing apparatus which is operable in a mode wherein copies are ejected onto a sheet tray or copies are transported to a sorter respectively, when a sheet jam takes place around the ejection port, an operator only has to pull out the jammed sheet because the ejection port protrudes outside. Even in this case, in order to start the jam reaction resetting operation, the operator has to open and close the outside frame, which is unnecessary for removing the jammed sheet.
Meanwhile, there has been popularized a copying system which is provided with or is optionally supplied with a sheet refeeder for feeding copy sheets, each of which gained an image on one side in the body of a copying apparatus and ejected therefrom, back to the body for a duplex or composite copying operation. Some copying systems have sheet refeeders, and the others do not. Further, regarding copying systems provided with sheet refeeders, some of them have switches for detecting the sheet refeeder recovering from a sheet jam, and the others do not. Therefore, the best way of executing the sheet jam reaction resetting operation is different from type to type. It is, however, difficult to compose a program by which the system is controlled in every case, and also it is very troublesome to compose different programs according to the existence of each jam reaction reset means.